Geastrum pectinatum

Description

Geastrum pectinatum is an inedible species of mushroom belonging to the earthstar family. Although young specimens are spherical, fruit body development involves the outer layer of tissue splitting open like a star into 7 to 10 pointed rays that eventually bend back to point downward.

The spore sac is supported by a small radially wrinkled stalk. There is a distinct conical opening (peristome) at the top of the spore sac that is up to 8 mm (0.3 in) long. The mass of spores and surrounding cells within the sac, the gleba, is dark-brown and becomes powdery in mature specimens.

G. pectinatum has a cosmopolitan distribution and has been collected in various locations in Europe, North and South America, Asia, Australia, and Africa, where it grows on the ground in open woods.

Earthstars are inedible and have no culinary value.

Common names: Beaked Earthstar, Beret Earthstar.

Mushroom Identification

1. Spore Sac

   The pale grayish-blue to grayish-violet spore sac (often referred to as the bulb) is 1 to 3cm across and subglobose (in the form of a vertically compressed sphere) with a long, striated beak terminating in a small round pore via which spores emerge. The beak-to-spore sac connection is usually umbonate (the beak sitting in a shallow depression). The spore sac stands above its base separated by a short stalk that has no basal collar - this feature differentiates the Beaked Earthstar from the slightly smaller but otherwise very similar Striate Earthstar Geastrum striatum, which has a basal collar.

2. Ray Structure

   The outer peridium, which at maturity forms the base of the fruitbody, comprises six to nine irregular pointed rays up to 7cm across when fully expanded.

3. Spores

   Globose, warty, 5-6μm diameter excluding warts.

4. Spore Mass

   Dark brown.

5. Habitat

   Mainly found under conifers, particularly Yew, but sometimes with hardwood trees; reported also to appear in gardens and parkland very occasionally.

6. Season

   Fruiting in the autumn; long-lasting, and often visible all year round.

History

The basionym of this species dates from 1801 when the Beaked Earthstar was described scientifically by Christiaan Hendrik Persoon in his Synopsis Methodicae Fungorum and given the binomial scientific name Geastrum pectinatum by which it is generally known today.

Geastrum, the generic name, comes from Geo- meaning earth, and -astrum meaning a star. Earthstar it is, then. The specific epithet pectinatum means 'like a comb' and may be a reference to the comb-like striations around the 'beak'.

Synonyms

1. Geaster pectinatus (Pers.) Quél.

2. Geastrum plicatum Berk. (1839)

3. Geastrum tenuipes Berk. (1848)

4. Geastrum biplicatum Berk. & M.A.Curtis (1858)

5. Geastrum pectinatum var. tenuipes (Berk.) Cleland & Cheel (1915)

Photo sources:

Photo 1 - Author: Len Worthington (CC BY-SA 2.0)

Photo 2 - Author: Susanne Sourell (suse) (CC BY-SA 3.0)

Photo 3 - Author: Lord Mayonnaise (CC BY-SA 3.0)

Photo 4 - Author: Lukas from London, England (CC BY-SA 2.0)

Photo 5 - Author: Glen van Niekerk (primordius) (CC BY-SA 3.0)